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Lexical Tools

SD-Rules Optimization Results

I. The final set
As the result, we concluded case 2.3.4.5.1 is the final optimized set of SD-Rules in the corpus of Lexicon 2013 to include 73 (out of 96) SD-rules to reach:

  • system accuracy rate: 95.30%
  • system coverage rate: 95.01%
  • system performance: 1.9031

This set of SD-rules is expected to reach the same system performance when it is applied to other English corpora under the assumption that:

  • the characteristics of derivations are consistent between from Lexicon and the working general English domain.
    Lexicon is considered as a representable subset (in terms of derivations) for general English. Please refer to future work for this assumption.

II. The methodology
This approach is used to find the best set of SD-rules from a set of known candidate SD-rules. Theoretically, a complete set of SD-Rules can be obtained when more SD-rules are evaluated and added. This methodology provides a systematic approach to:

  • measure system performance
  • to evaluate new SD-rules
  • obtain the set of SD-rules according to user's specified target minimum accuracy rate (system performance)

III. The target accuracy rate (95%)

As shown in the previous session, the intersection of curves (optimization) of system accuracy rate and system coverage rate of the final set are at 95%. We also used average values for the window size of 3, 5, 7 rules for these two curves for noise reduction (smoothing algorithm - simple moving average) and find the intersections are all around 95% for all cases (see diagram below). Smoothing this data set allows us to capture the characteristics of this set and leave out noise. Accordingly, our target minimum accuracy rate (95%) is a good choice to obtain the optimized set of SD-rules (close to optmization).